Final answer:
The repair of the peripheral nervous system involves a sequence where Nissl bodies break down, axon and myelin degrade distal to the injury, Schwann cells proliferate to form a growth tube, and axon buds grow within the tube to restore connections.
Step-by-step explanation:
When the peripheral nervous system undergoes injury, a specific sequence of events facilitates the repair process. Initially, Nissl bodies within the injured neuron's cell body disaggregate into fine granules, indicating a shift in the neuron's metabolic state in response to injury. This is followed by the degradation of axon and myelin sheath distal to the injury site, which is essential for clearing the path for new growth. Schwann cells, known for producing the myelin sheath on axons in the peripheral nervous system, undergo mitosis and form a regenerative tube. This tube not only serves as a scaffold but also secretes growth factors to facilitate axon regeneration. Consequently, axon buds grow down the tube, eventually reestablishing functional connections.
The process of myelination, where the myelin sheaths are created around the axons by Schwann cells, is crucial both in the initial development of the nervous system and in repair mechanisms. Schwann cells and myelin sheaths are central to the efficient conduction of nerve impulses via nodes of Ranvier, allowing rapid transmission across the nervous system.